Denham and Fairoaks also lie within the Heathrow CTA but have notified routes.
Just to clarify - it is not necessary to have owt to do with SVFR to get into / out of Fairoaks, providing that one enters / leaves the Fairoaks ATZ from the South or SW - i.e. from outside the Heathrow Zone.
I believe the same is true for Denham, arriving / departing to the North.
That portion of the ATZ for these airfields (also White Waltham) that is
under the Heathrow zone is
NOT class A airspace. In the case of Fairoaks, the ATZ extends from sfc to 1400' QNH - above that, you need an SVFR!
I have arrived / departed Fairoaks SVFR several times - not at all difficult, the guys at LHR radar are very helpful.